1. Field of the Invention
This invention relates to a transfer apparatus for transferring a plate-like member such as a semiconductor wafer and storing it in a storage body.
2. Description of the Related Art
A well-known example of the transfer apparatuses for transferring semiconductor wafers and storing them in a storage body is one which has been disclosed in Japanese Patent Disclosure No. 84-175740. In this transfer apparatus, a semiconductor wafer that has arrived after passing through the transfer path is loaded on an arm and secured thereto by vacuum chucking. By moving the arm through a wafer cassette as a storage body the semiconductor wafer is transferred to and stored in a predetermined position of the wafer cassette.
Since a semiconductor wafer is transferred while it is loaded on the arm and absorbed thereto, there is a possibility that a wafer is loaded in a position deviating from a predetermined position. As a result, the wafer comes into contact with the side wall of a wafer cassette while the wafer is transferred. When a wafer comes into contact with the side wall of a wafer cassette, it can happen that the wafer becomes unable to move and cannot be stored in the cassette or is broken or is stored in an imperfect way, presenting difficulty in taking out the wafer later on. Another problem is that if the edge of the wafer is broken, there will be resulting fractions of wafer.